Divide the classroom into an even number of groups, and make a knock-out competition table on the board, pitting two groups at a time against each other. In each round, select a topic to debate, such as immigration, freedom of speech, or economy versus environment. One group must be for and the other against an issue. Ask students to research their topic as a group, and require each member to prepare a one-minute speech. Have the students forming the audience vote for the group with the most influential speeches and arguments.
Divide students into two groups, and ask each to put on a short theatrical play -- about 20 minutes long -- that will be presented in one of the next classes. Every student must have a role, no matter how small. Provide some guidance with respect to themes, but let students do most of the plot legwork. This is a great way for students can practice their English speaking skills while expressing different emotions, such as anger, joy and sadness.
Divide the class into two groups and ask them to chose one leader. Then, write a word on the board and ask students to write as many synonyms and antonyms as they can think of within five minutes. Students must work together, discuss, brainstorm and write down their answers. After five minutes, the leaders of the groups must stand up and read their teams' answers aloud. The group with the most correct answers in the winner.
Break students into teams, and take turns challenging them to either define words, or provide the word for a given definition. There are many ways of orchestrating this activity. Questions can be printed on handouts, teams can compete Jeopardy-style, or you can frame the game as a trivia-type game. The main goal is that all students have a chance to collaborate with each other, as well as participate independently.